Palo Alto Networks Staff Engineer Interview Questions and Answers

IP packet header fields and their usage

• Version: indicates the IP version being used (IPv4 or IPv6)

• Header Length: specifies the length of the IP header

• Type of Service: used to prioritize packets

• Total Length: specifies the total length of the IP packet

• Identification: used to identify fragments of a larger packet

• Flags: used to control fragmentation

• Fragment Offset: used to reassemble fragmented packets

• Time to Live: specifi...read more

TCP packet header fields and their usage

• TCP packet header consists of 20 bytes

• Fields include source and destination ports, sequence and acknowledgement numbers, flags, window size, and checksum

• Source and destination ports identify the endpoints of the connection

• Sequence and acknowledgement numbers are used for reliable data transfer

• Flags indicate the purpose of the packet, such as SYN, ACK, FIN, RST

• Window size is used ...read more

A program to implement a dictionary using an array of strings.

• Use an array of strings to store the words and their definitions.

• Implement functions to add, delete, and search for words.

• Consider using a hash table for faster search times.

Implement a telephone directory program using an array of strings.

• Create an array of strings to store the directory

• Implement functions to add, delete, and search for entries

• Consider using a hash table for faster search times

• Include error handling for invalid input

TCP is a reliable, connection-oriented protocol while UDP is a faster, unreliable, connectionless protocol.

• TCP ensures data delivery and error checking while UDP does not.

• TCP establishes a connection before data transfer while UDP does not.

• TCP is used for applications that require reliable data transfer like email, file transfer, etc. while UDP is used for applications that require speed like online gaming, video strea

Security is important in a system to protect against unauthorized access, data breaches, and cyber attacks.

• Prevents unauthorized access to sensitive data

• Protects against data breaches and cyber attacks

• Ensures confidentiality, integrity, and availability of data

• Compliance with regulations and standards

• Maintains trust and confidence of customers and stakeholders

Printing a tree in level order

• Use a queue to store nodes in level order

• Enqueue root node and print its value

• Dequeue the node and enqueue its children

• Repeat until queue is empty

Swapping two particular bits of an integer program.

• Use bitwise operators to get the values of the two bits to be swapped

• Use XOR operator to swap the bits

• Shift the bits back to their original positions

• Example: Swapping 2nd and 5th bits of 8 (1000) gives 32 (100000)

• Example code: num ^= (1 << bit1) | (1 << bit2);